ZnS/Zn-MOFs@SC superhydrophobic coatings mimicking layered stone structures enhance anti-fouling, corrosion resistance, and antibacterial properties of magnesium alloys

Magnesium alloys are promising for biodegradable medical devices due to their low density, high specific strength, and excellent biocompatibility. However, their rapid corrosion, protein fouling, and bacterial adhesion severely limit clinical applications. Here, a stratified-rock-inspired micro/nano-structured ZnS/Zn-MOFs coating was fabricated on AZ31B via a one-step hydrothermal route and post-functionalized with stearic acid (SA) and chloramphenicol (CAP) to afford a superhydrophobic ZnS/Zn-MOFs@SC surface (water contact angle ≈ 164°). The coating retained its superhydrophobicity after ultrasonication, adhesive-tape peeling, and sandpaper abrasion. Electrochemical measurements revealed that the corrosion current density (I corr ) decreased from ∼10 -3 A cm −2 (bare alloy) to 7.66 × 10 -7 A cm −2 , corresponding to a four-order-of-magnitude improvement, while the diameter of the capacitive loop in the Nyquist plot increased by five orders of magnitude. In vitro bacterial tests show the coating fully prevents bacterial adhesion. The inhibition zones for E. coli and S. epidermidis reach 3.1 cm and 4.4 cm. And it has been established that bacterial growth levels below the detection limit (10 5 CFU cm −2 ) cannot effectively evaluate its antimicrobial efficacy. These results demonstrate that the ZnS/Zn-MOFs@SC coating simultaneously provides robust corrosion protection, anti-fouling, and antibacterial activities, offering great potential for next-generation biodegradable implants.